Water injection system for aircraft



April 13, 1948. M. BERGMAN 'ATER INJECTION SYSTEH FOR AIRCRAFT Filed lay8, 1946 J v www@ Bergman www' SEQ Smal @SQA SEQ heb mt 5382@ .ESG

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Patented 13., l948 OFFICE ammo wA'rl-:n nunc'rrox srs'rmr ronAntolin-"rA Mendel Bergman, United States Navy Application MI! 8, 1948,Serial No. 868,051

'z 0mm. (ci. 12s-2s) (Granted under the act of March 8, 1883, as

amended April 30, 1928: 370 0. G. 757) This invention relates toimprovements in the water injection system for aircraft and particularlyto remedies for the present existing defects in the system.

The existing water injection system enables the pilot to obtain anincrease of as much as 250 H. P. at full throttle for a limited periodof timeV (eight to ten minutes). This extra horsepower is very useful incritical combat situations demanding extra power. The higher horsepoweris obtained by leaning out the carburetor mixture and increasing themanifold pressure automatically when the pilot turns on the waterinjection system. Of the increase in power over military rating obtainedwith this emergency power;` approximately one half is due to the leaningout the mixture to best power and the other half due to the increase inmanifold pressure. Ordinarily these changes would result in highcylinder temperatures and damage to the engine due to detonation, butwhen a ,water and alcohol mixture is introduced with the fuel at theimpeller spinner nozzle, the cooling effect is suilicient to maintainnormal cylinder temperatures and suppress any tendency towarddetonation;

However, this previously existing water injection system i-s notintended for use during takeoil. Nevertheless it is necessary to pointout the adverse conditions that will result from its inadvertent use.During normal operation of certain engines, the water discharge linebecomes filled With fuel. This extra fuel is forced into the engine whenthe water injection equipment is actuated. The resultant excessivelyrich mixture causes the engine to hesitate or stumble for an instant.Pilots who have used water injection are familiar with this hesitationand an attempt to described its magnitude can not replace actualexperience in flight. Obviously the use of water injection at the lastmoment before a crash appears imminent, will probably make the crash acertainty. i

If towards the end of take-oil run using takeoll' power, it is decidedthat additional power is necessary, the pilot must be extremelycarefulnot to actuate the water injection `equipment; when increasingthe power.' `In this connection it is necessary for pilots tofamiliarize themselves with the design and operation of the waterinjection equipment. They must be particularly careful that the pump ofthe master switch should be on the "oiT position-before the take-ofi',In certain cases, water injection is automatically obtained at fullthrottle. To avoid inadvertent use of water in these airplanes it isnecessary that the safety wire on the throttle quadrant be replaced eachtime it is broken.

The purpose of this invention is to improve the operation oi' theconventional water injection system so that it will no longer behazardous to accidentally operate the water injection system duringtake-oil. and to make it possible to use water injection for assistingheavily loaded airplanes to take-oil.' on a limited runway.

Details of the invention are described in connection with the followingdrawing in which the figure is a schematic, diagrammatic view of theimproved features of this invention as added to the conventionalexisting water injection system.

When throttle valve control lever I is pushed to the wide open positionbreaking the safety l wire on the throttle quadrant the electric pushbutton switch-2 which actuates the water injection system, closes theelectric circuit to the water injection system and the following eventsoccur:

Electrically operated pump 3 is started; ythe yelectric solenoidactuated valve I which is located near the entrance of water regulator 5is opened and the vcircuit of the water quantity transmitter l isclosed. A water pressure `of approximately 17.5 p. s. i. builds Vupalmost instantly while the excess water, the vapor and air are returnedto the water tank through bleed return line 'l on the upstream side ofelectric solenoid valve 4.

yThe water and alcohol solution -flows through open solenoid valve 4 andscreen to water regulator 5. The water pressure opens check valve t atthe entrance to the water regulator and builds up pressure in unmeteredwater chamber 9 of the water regulator. Two water lines lead from theunmetered water chamber of the water regulator; one of these indicatedas I0 leads to the carburetor derichment "valve chamber II u where thewater pressure leans out fuel mixture from approximately nine to oneair-fuel ratioto approximately fourteen to `one air-fuel ratio.

The other. line indicated as I2 goes to the auxiliary superchargerregulator gate valve chamber L the carburetor to the main superchargerimpeller.

Water enters the engine induction system with the fuel at approximatelya ratio of one part of water to five parts of fuel. The first water toflow pushes the fuel in water regulator 5 and water transfer line I1(which may back up as far as check valve 8 when the water pressure isoil) back to the supercharger or spinner discharge nozzle. This causes amomentary over rich mixture and the engine will hesitate briefly. Undernormal conditions the engine will respond to the water injection systemwithin three to five seconds after system is switched on.` As thus fardescribed, this is the conventional existing'water injection system.

It has been found that the systemcan be improved by adding three itemsof this invention to the hookup of the conventional existing waterinjection system. These three additional items of this invention willallow the existing water injection system to be used for take-oil andtheir use is so designed to eliminate' the hesitation or stumble of theengine whenv water injection is used for take-on. An electric solenoidvalve 20 is located at the banjo or water-regulator 5, the auxiliarysupercharger regulator I4, and the derichment valve chamber Thiselectric solenoid valve 20 is also connected to the push button switch 2and is in parallel electrical hookup with the other electricsolenoidvalve 4 located near the entrance to the water regulator. In order tomaintain discharge nozzle pressure in the water, regulator 5, auxil,iary supercharger regulator i4, and derichment valve chamber it isnecessary to install a low pressure accumulator 2| with an extremelyexible diaphragm 22 on the side of the carburetor. One chamber 23 of theaccumulator is connected to the fuel chamber of the carburetor havingengine pump pressure, and the other chamber 24 oi.' the accumulator isconnected to the derichment valve chamber of the carburetor. t

In addition, it is necessary to install a filler opening (vent) and plug25 in the water chamber ofthe auxiliary supercharger regulator so thatthe auxiliary supercharger regulator, water regulator, and carburetorderichment valve chamber may (be filled and primed with thewater-alcohol solution at the same time that the tanks of the Waterinjection system are filled dwith the water-alcohol solution.

After the water injection system has been turned' on, the pressure inthe water-alcohol solution side 24 ofthe accumulator 2| will increasefrom the engine pump pressure (4 to 6 p. s. i.) to water pump pressure`(17.5 p. s. l.) and will therefor lmove the accumulator diaphragm 22towards the fuel side 23 of the accumulator 2|. This will naturallyforce the fuel from 4the accumulator 2l into the chamber of the carbu' 45 carburetor to increase enough to open the poppet valve of thecarburetor regulator unit any farther than necessary and therefore thecorrect mixture will be maintained.

The invention described herein may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

What I claim is:

1. In an internal combustion engine carburetor i having a waterinjection system wherein fuel from the carburetor passes throughl a fueltransfer line to a double banjo or T fitting to mix with water passingthrough a water transfer line from the water injection system and thenpass via the fitting through a mixture transfer line to the intake ofthe engine, and wherein fer line to a double banjo or T fitting to mixwith water passing through a water transfer transfer. line and cause theengine to momentarily .lose power when the water injection system isline from the water injection system and'then pass via the fittingthroughs mixture transfer line to the intake of the engine, and whereinthe fuel, being lighter, tends to replace the water in the watertransfer line and thus momentarily cause an ovenich fuel mixture toenter the mixture transfer line and cause the engine to momentarily losepower when the water injection system is first actuated; means formaintaining water in the water transfer line and prevent-ing the- -asolenoid valve in the-water transfer line located closely adjacent thebanjo or T fitting.

- 3. In an internal combustion engine carburetor having a waterinjection system wherein fuel from the carburetor passes through a fueltransfer line to a double banjo T fitting to mix with water passingthrough a, water transfer linefrom the water injection system and thenpass via the litt-ing through a mixture transfer line to the intake` ofthe engine, and wherein the fuel, being lighter, tends to replace thewater in the water transfer line and thus momentarily cause an overrichfuel mixture to enter the mixture first actuated; and means formaintaining water in the 'water transfer line and preventing the fuelfrom replacing it while the water injection system is unactuated andmeans for actuating the water maintaining means to pass the water to thefitting simultaneously with the actuation of ,the water injection systemand thus cause an immediate increase in engine power.

4. In an internal combustion engine carburetor `having a'water injectionsystem wherein fuel from the carburetor passes through a. fuel transferline to a double banjo or T fitting to mix with water passing through awater transfer line from the water injection system and then pass viathe fitting through a mixture transfer line to the intake of the engine,and wherein the fuel, being maaar@ lighter, tends to replace the waterin the water transfer line and thus momentarily cause an overrich fuelmixture to enter the mixture transfer line and cause the engine tomomentarily lose power when the water injection system is firstactuated; means for maintaining water in the `water transfer line andpreventing the fuel from replacing it while the Water injection systemis unactuated and means for actuatingthe water maintaining means to passthe water to the fitting simultaneously with the actuation of the waterinjection system and thus cause an immediate increase in engine power,said actuating means comprising a circuit connecting said solenoid valveto the circuit actuating the water injection system.

5. In an internal combustion engine carburetor having a water injectionsystem wherein fuel from the carburetor passes through a fuel transferline to a double banjo or TI tting to mix with water passing through awater transfer line from the` water injection system and then pass vlathe fltunactuated and means for actuating the water maintaining means topass the water to the fitting simultaneously with the actuation of thewater injection system and thus cause an immediate increase in enginepower, said actuating means comprising a circuit connecting saidsolenoid valve to the circuit actuating the water inlection system andvent or filler means in the water injection system.

6. In an internal combustion engine carburetor having a water injectionsystem wherein fuel from the carburetor passes through a fuel transferline to a double banjo or T fitting to mix with water passing through awater transfer line from the water injection system and then pass viathe fitting through a mixture transfer line to lthe intake of theengine, and wherein the fuel,

being lighter, tends to replace the water in the water transfer line andthus momentarily cause an overrich fuelmixture to enter the mixturetransfer line and cause the engine to momentarily lose power when thewater injection system is first actuated; means for maintaining water inthe water transfer line and preventingthefuel from replacing it whilethe water injection sys- Y tern is unactuated, means for actuating thewater maintaining means to pass the Water to the fitmediatevincrease inengine power, said actuating means comprising a circuit connecting saidsolenoid valve to the circuit actuating the water injection system, andmeans for somewhat increasing the engine pump pressure of the carburetorcomprising 4a differential pressure accumulator connected to the enginepump pressure chamber of the carburetor.

7. In an internal combustion engine carburetor having a water injectionsystem wherein fuel from the carburetor passes through a fuel transferline to a double banjo or T fitting to mix with water passing through awater transfer line from the water injection system and then pass viathe fitting through a mixture transfer line to the intake of the engine,and wherein 'the fuel, being lighter, tends to replace the water in thewater transfer line and thus momentarily cause an overrich fuel mixtureto enter the mixture transfer line and cause the engine to momentarilylose power when the water injection system. is first actuated; means formaintaining water in the water transfer line and preventing the fuelfrom replacing it while the water injection system is unactuated, `saidmeans comprising a solenoid valve in the water transfer line locatedclosely adjacent the banjo or T fitting, and means for actuating f thewater maintaining means to pass the water to the fitting simultaneouslywith the actuation of the water injection system and thus causeanimmediate increase in engine power, said actuating means comprising acircuit connecting sai-d solenoid valve to the circuit actuating thewater injection system. Y

MENDEL BERGMAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS l France May 1s, 193s Certificate of CorrectionPatent No. 2,439,379. April 13, 1948.

MENDEL BERGMAN It is hereby certified that errors appear in the printedspecification of the above numbered patent requiring correction asfollows: Column 2, line 46, after the Word regulator insert 14; column8, lines 1 and 9, after nozzle insert valve; and that the said LettersPatent should be read with these corrections therein that the same mayconform to the record of the ease in the Patent JOfIce.

Signed and sealed this 8th day of June', A. D. 1948.

[SEAL] THOMAS F. MURPHY,

Assistant mmm'ssz'oner of Patents.

